Heart disease risk: impact of pollution, overtime

It’s a busy week in heart health news. The American Heart Association (AHA) released a new statement (PDF) yesterday on the impact of particulate pollution on heart health — suggesting that there is now enough evidence to indicate that this form of fine pollution can contribute to heart disease and even trigger heart attacks. Meanwhile, a study that will be published online in the European Heart Journal suggests that people who regularly work overtime are at higher risk for heart attack, heart disease and other cardiovascular complications. (Or, in less scientific terms, it appears you really may be able to work yourself to death.)

The new AHA statement is based on a review of dozens of studies conducted in the past six years exploring the impact of fine particle pollution on heart health, NPR reports. The findings aren’t encouraging. As Dr. Robert Brook, a heart specialist and professor at the University of Michigan in Ann Arbor, told NPR:

“We can say for first time that the evidence is consistent enough now to say that there’s a causal relationship between air pollution exposure and cardiovascular disease… We have a greater number, quality and depth of epidemiological studies that show stronger linkage than we previously thought.”

Brook points to studies showing that people who live closer to roadways have higher risk of cardiovascular complications than those who live farther away, and that concentrated exposure can even trigger heart attacks in otherwise healthy people, NPR reports. Researchers believe that fine particle pollution is inhaled into the lungs, where it can cause inflammation leading to other health complications including heart disease. (In a more optimistic view of the issue, a study published last year in the New England Journal of Medicine found that, when pollution levels are reduced, life expectancy can go up by as much as five months.)

To determine whether work duration influences heart health, a team of researchers from Finland, the U.K. and France analyzed data for more than 6,000 workers between the ages of 39 to 61 who were followed from 1991-1994 to 2002-2004. They found that, compared with those who didn’t work more than an average of seven hours per day, employees who slogged along for more than 10 hours each day faced a 60% higher risk of heart complications — including heart disease-related death and heart attack. This correlation persisted even after controlling for factors such as smoking, overweight, and high cholesterol.

In an editorial that accompanies the study, Dr. Gordon T. McInnes of the University of Glasgow examines the study’s shortcomings — noting among other things that certain people may be more likely to work overtime while sick, increasing their risk for cardiovascular events, and pointing out that work stress likely functions along with other factors to influence overall risk for heart disease. Yet, in spite of these concerns, he finds that, “these data from a large occupational cohort reinforce the notion that work stress attributable to overtime is associated, apparently independently, with an increased risk of coronary heart disease.”

McInnes suggests that this latest study adds to a growing body of research suggesting that work-related stress has significant influence and health outcomes, and stresses that future research is vital for determining whether reduced work hours would yield substantial health benefits. And then he closes with this thought:

“A suitable summation is suggested by the words of the great English philosopher, Bertrand Russell: ‘If I were a medical man, I should prescribe a holiday to any patient who considers work important.'”